n8n Expression Examples

Real working examples from n8n workflows.

Example 1: Webhook Form Submission

Scenario: Form submission webhook posts to Slack

Workflow: Webhook → Slack

Webhook Input (POST):

{
  "name": "John Doe",
  "email": "john@example.com",
  "company": "Acme Corp",
  "message": "Interested in your product"
}

Webhook Node Output:

{
  "headers": {"content-type": "application/json"},
  "params": {},
  "query": {},
  "body": {
    "name": "John Doe",
    "email": "john@example.com",
    "company": "Acme Corp",
    "message": "Interested in your product"
  }
}

In Slack Node (text field):

New form submission! 📝

Name: {{$json.body.name}}
Email: {{$json.body.email}}
Company: {{$json.body.company}}
Message: {{$json.body.message}}

Output:

New form submission! 📝

Name: John Doe
Email: john@example.com
Company: Acme Corp
Message: Interested in your product

Example 2: HTTP API to Database

Scenario: Fetch user data from API and insert into database

Workflow: Schedule → HTTP Request → Postgres

HTTP Request Returns:

{
  "data": {
    "users": [
      {
        "id": 123,
        "name": "Alice Smith",
        "email": "alice@example.com",
        "role": "admin"
      }
    ]
  }
}

In Postgres Node (INSERT statement):

INSERT INTO users (user_id, name, email, role, synced_at)
VALUES (
  {{$json.data.users[0].id}},
  '{{$json.data.users[0].name}}',
  '{{$json.data.users[0].email}}',
  '{{$json.data.users[0].role}}',
  '{{$now.toFormat('yyyy-MM-dd HH:mm:ss')}}'
)

Result: User inserted with current timestamp

Example 3: Multi-Node Data Flow

Scenario: Webhook → HTTP Request → Email

Workflow Structure:

Webhook receives order ID
HTTP Request fetches order details
Email sends confirmation

Node 1: Webhook

Receives:

{
  "body": {
    "order_id": "ORD-12345"
  }
}

Node 2: HTTP Request

URL field:

https://api.example.com/orders/{{$json.body.order_id}}

Returns:

{
  "order": {
    "id": "ORD-12345",
    "customer": "Bob Jones",
    "total": 99.99,
    "items": ["Widget", "Gadget"]
  }
}

Node 3: Email

Subject:

Order {{$node["Webhook"].json.body.order_id}} Confirmed

Body:

Dear {{$node["HTTP Request"].json.order.customer}},

Your order {{$node["Webhook"].json.body.order_id}} has been confirmed!

Total: ${{$node["HTTP Request"].json.order.total}}
Items: {{$node["HTTP Request"].json.order.items.join(', ')}}

Thank you for your purchase!

Email Result:

Subject: Order ORD-12345 Confirmed

Dear Bob Jones,

Your order ORD-12345 has been confirmed!

Total: $99.99
Items: Widget, Gadget

Thank you for your purchase!

Example 4: Date Formatting

Scenario: Various date format outputs

Current Time: 2025-10-20 14:30:45

ISO Format

{{$now.toISO()}}

Output: 2025-10-20T14:30:45.000Z

Custom Date Format

{{$now.toFormat('yyyy-MM-dd')}}

Output: 2025-10-20

Time Only

{{$now.toFormat('HH:mm:ss')}}

Output: 14:30:45

Full Readable Format

{{$now.toFormat('MMMM dd, yyyy')}}

Output: October 20, 2025

Date Math - Future

{{$now.plus({days: 7}).toFormat('yyyy-MM-dd')}}

Output: 2025-10-27

Date Math - Past

{{$now.minus({hours: 24}).toFormat('yyyy-MM-dd HH:mm')}}

Output: 2025-10-19 14:30

Example 5: Array Operations

Data:

{
  "users": [
    {"name": "Alice", "email": "alice@example.com"},
    {"name": "Bob", "email": "bob@example.com"},
    {"name": "Charlie", "email": "charlie@example.com"}
  ]
}

First User

{{$json.users[0].name}}

Output: Alice

Last User

{{$json.users[$json.users.length - 1].name}}

Output: Charlie

All Emails (Join)

{{$json.users.map(u => u.email).join(', ')}}

Output: alice@example.com, bob@example.com, charlie@example.com

Array Length

{{$json.users.length}}

Output: 3

Example 6: Conditional Logic

Data:

{
  "order": {
    "status": "completed",
    "total": 150
  }
}

Ternary Operator

{{$json.order.status === 'completed' ? 'Order Complete ✓' : 'Pending...'}}

Output: Order Complete ✓

Default Values

{{$json.order.notes || 'No notes provided'}}

Output: No notes provided (if notes field doesn't exist)

Multiple Conditions

{{$json.order.total > 100 ? 'Premium Customer' : 'Standard Customer'}}

Output: Premium Customer

Example 7: String Manipulation

Data:

{
  "user": {
    "email": "JOHN@EXAMPLE.COM",
    "message": "  Hello World  "
  }
}

Lowercase

{{$json.user.email.toLowerCase()}}

Output: john@example.com

Uppercase

{{$json.user.message.toUpperCase()}}

Output: HELLO WORLD

Trim

{{$json.user.message.trim()}}

Output: Hello World

Substring

{{$json.user.email.substring(0, 4)}}

Output: JOHN

Replace

{{$json.user.message.replace('World', 'n8n')}}

Output: Hello n8n

Example 8: Fields with Spaces

Data:

{
  "user data": {
    "first name": "Jane",
    "last name": "Doe",
    "phone number": "+1234567890"
  }
}

Bracket Notation

{{$json['user data']['first name']}}

Output: Jane

Combined

{{$json['user data']['first name']}} {{$json['user data']['last name']}}

Output: Jane Doe

Nested Spaces

Contact: {{$json['user data']['phone number']}}

Output: Contact: +1234567890

Example 9: Code Node (Direct Access)

Code Node: Transform webhook data

Input (from Webhook node):

{
  "body": {
    "items": ["apple", "banana", "cherry"]
  }
}

Code (JavaScript):

// ✅ Direct access (no {{ }})
const items = $json.body.items;

// Transform to uppercase
const uppercased = items.map(item => item.toUpperCase());

// Return in n8n format
return [{
  json: {
    original: items,
    transformed: uppercased,
    count: items.length
  }
}];

Output:

{
  "original": ["apple", "banana", "cherry"],
  "transformed": ["APPLE", "BANANA", "CHERRY"],
  "count": 3
}

Example 10: Environment Variables

Setup: Environment variable API_KEY=secret123

In HTTP Request (Headers)

Authorization: Bearer {{$env.API_KEY}}

Result: Authorization: Bearer secret123

In URL

https://api.example.com/data?key={{$env.API_KEY}}

Result: https://api.example.com/data?key=secret123

Template from Real Workflow

Based on n8n template #2947 (Weather to Slack)

Workflow Structure

Webhook → OpenStreetMap API → Weather API → Slack

Webhook Slash Command

Input: /weather London

Webhook receives:

{
  "body": {
    "text": "London"
  }
}

OpenStreetMap API

URL:

https://nominatim.openstreetmap.org/search?q={{$json.body.text}}&format=json

Weather API (NWS)

URL:

https://api.weather.gov/points/{{$node["OpenStreetMap"].json[0].lat}},{{$node["OpenStreetMap"].json[0].lon}}

Slack Message

Weather for {{$json.body.text}}:

Temperature: {{$node["Weather API"].json.properties.temperature.value}}°C
Conditions: {{$node["Weather API"].json.properties.shortForecast}}

Summary

Key Patterns:

Webhook data is under .body
Use {{}} for expressions (except Code nodes)
Reference other nodes with $node["Node Name"].json
Use brackets for field names with spaces
Node names are case-sensitive

Most Common Uses:

{{$json.body.field}} - Webhook data
{{$node["Name"].json.field}} - Other node data
{{$now.toFormat('yyyy-MM-dd')}} - Timestamps
{{$json.array[0].field}} - Array access
{{$json.field || 'default'}} - Default values

Related: See COMMON_MISTAKES.md for error examples and fixes.

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